Conventionally, there is a known heat pump cooling and heating device that determines a shortage of a refrigerant in a cycle, based on the pressure of a high-pressure refrigerant in the cycle and thereby protects a compressor when the cycle is determined to be running short of the refrigerant (see, e.g., Patent Document 1).
Specifically, Patent Document 1 discloses that the operation of the compressor is stopped because of the shortage of the refrigerant when the pressure of the high-pressure refrigerant in the cycle becomes equal to or lower than a pressure value, which is slightly higher than the atmospheric pressure, after a predetermined time has elapsed since the start of the operation of the compressor.
Patent Document 1: Japanese Unexamined Patent Application Publication No. H08-313123